IB/core: Assign root to all drivers

In order to use the parsing tree, we need to assign the root
to all drivers. Currently, we just assign the default parsing
tree via ib_uverbs_add_one. The driver could override this by
assigning a parsing tree prior to registering the device.

Signed-off-by: Matan Barak <[e-mail]>
Reviewed-by: Yishai Hadas <[e-mail]>
Signed-off-by: Doug Ledford <[e-mail]>

drivers/infiniband/core/uverbs.h

···
 	struct mutex				lists_mutex; /* protect lists */
 	struct list_head			uverbs_file_list;
 	struct list_head			uverbs_events_file_list;
+	struct uverbs_root_spec			*specs_root;
 };
 
 struct ib_uverbs_event_queue {

drivers/infiniband/core/uverbs_main.c

···
 #include <linux/uaccess.h>
 
 #include <rdma/ib.h>
+#include <rdma/uverbs_std_types.h>
 
 #include "uverbs.h"
 #include "core_priv.h"
···
 	if (device_create_file(uverbs_dev->dev, &dev_attr_abi_version))
 		goto err_class;
 
+	if (!device->specs_root) {
+		const struct uverbs_object_tree_def *default_root[] = {
+			uverbs_default_get_objects()};
+
+		uverbs_dev->specs_root = uverbs_alloc_spec_tree(1,
+								default_root);
+		if (IS_ERR(uverbs_dev->specs_root))
+			goto err_class;
+
+		device->specs_root = uverbs_dev->specs_root;
+	}
+
 	ib_set_client_data(device, &uverbs_client, uverbs_dev);
 
 	return;
···
 		ib_uverbs_comp_dev(uverbs_dev);
 	if (wait_clients)
 		wait_for_completion(&uverbs_dev->comp);
+	if (uverbs_dev->specs_root) {
+		uverbs_free_spec_tree(uverbs_dev->specs_root);
+		device->specs_root = NULL;
+	}
+
 	kobject_put(&uverbs_dev->kobj);
 }
 

include/rdma/uverbs_ioctl.h

···
  * An object without any methods is considered invalid and will abort the
  * function with -ENOENT error.
  */
+#if IS_ENABLED(CONFIG_INFINIBAND_USER_ACCESS)
 struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
 						const struct uverbs_object_tree_def **trees);
 void uverbs_free_spec_tree(struct uverbs_root_spec *root);
+#else
+static inline struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
+							      const struct uverbs_object_tree_def **trees)
+{
+	return NULL;
+}
+
+static inline void uverbs_free_spec_tree(struct uverbs_root_spec *root)
+{
+}
+#endif
 
 #endif

include/rdma/uverbs_std_types.h

···
 #define _UVERBS_STD_TYPES__
 
 #include <rdma/uverbs_types.h>
+#include <rdma/uverbs_ioctl.h>
 #include <rdma/ib_user_ioctl_verbs.h>
 
+#if IS_ENABLED(CONFIG_INFINIBAND_USER_ACCESS)
 extern const struct uverbs_object_def uverbs_object_comp_channel;
 extern const struct uverbs_object_def uverbs_object_cq;
 extern const struct uverbs_object_def uverbs_object_qp;
···
 extern const struct uverbs_object_def uverbs_object_pd;
 extern const struct uverbs_object_def uverbs_object_xrcd;
 extern const struct uverbs_object_def uverbs_object_device;
+
+extern const struct uverbs_object_tree_def uverbs_default_objects;
+static inline const struct uverbs_object_tree_def *uverbs_default_get_objects(void)
+{
+	return &uverbs_default_objects;
+}
+#else
+static inline const struct uverbs_object_tree_def *uverbs_default_get_objects(void)
+{
+	return NULL;
+}
+#endif
 
 static inline struct ib_uobject *__uobj_get(const struct uverbs_obj_type *type,
 					    bool write,